This application relates to a weight reduction technique for use in rotating blades in gas turbine engines.
Gas turbine engines are known and, typically, include a fan delivering air into a compressor. The air is compressed and delivered into a combustion section where it is mixed with fuel and ignited. Products of this combustion pass downstream over turbine rotors, driving them to rotate. The turbine rotors, in turn, drive rotors associated with both the compressor and fan sections.
Historically, a single turbine may have driven the fan rotor in a low pressure compressor rotor. However, more recently, a gear reduction has been provided between the fan and the turbine drive. With this gear reduction, the fan can rotate at slower speeds than the turbine or the low pressure compressor.
As the speed of the fan has decreased, there has been an increase in the size of the fan blades. The fan typically also delivers air into a bypass duct where it becomes propulsion for an associated aircraft. The volume of air delivered into the bypass duct has increased relative to the volume of air delivered into the compressor with the enlarged blades.
However, as the blades become larger, their weight also becomes undesirably large.